Select Board & Class
What are the differences between Tropism and Nastic Movement?
''small intestine is the site of the complete digestion of carbohydrates ,fats and proteins".Explain how it performs that function..
What is the difference between motor and sensory neurons?
Could anyone explain the meaning of these lines:Transmission of Nerve Impulse The transmission of a nerve impulse along a neuron from one end to the other occurs as a result of electrical changes across the membrane of the neuron. The membrane of an unstimulated neuron is polarized—that is, there is a difference in electrical charge between the outside and inside of the membrane. The inside is negative with respect to the outside. Polarization is established by maintaining an excess of sodium ions (Na+) on the outside and an excess of potassium ions (K+) on the inside. A certain amount of Na+ and K+ is always leaking across the membrane through leakage channels, but Na+/K+ pumps in the membrane actively restore the ions to the appropriate side. The main contribution to the resting membrane potential (a polarized nerve) is the difference in permeability of the resting membrane to potassium ions versus sodium ions. The resting membrane is much more permeable to potassium ions than to sodium ions resulting in slightly more net potassium ion diffusion (from the inside of the neuron to the outside) than sodium ion diffusion (from the outside of the neuron to the inside) causing the slight difference in polarity right along the membrane of the axon.Other ions, such as large, negatively charged proteins and nucleic acids, reside within the cell. It is these large, negatively charged ions that contribute to the overall negative charge on the inside of the cell membrane as compared to the outside. In addition to crossing the membrane through leakage channels, ions may cross through gated channels. Gated channels open in response to neurotransmitters, changes in membrane potential, or other stimuli. The following events characterize the transmission of a nerve impulse: Resting potential. The resting potential describes the unstimulated, polarized state of a neuron (at about 70 millivolts). Graded potential. A graded potential is a change in the resting potential of the plasma membrane in the response to a stimulus. A graded potential occurs when the stimulus causes Na+ or K+ gated channels to open. If Na+ channels open, positive sodium ions enter, and the membrane depolarizes (becomes more positive). If the stimulus opens K+ channels, then positive potassium ions exit across the membrane and the membrane hyperpolarizes (becomes more negative). A graded potential is a local event that does not travel far from its origin. Graded potentials occur in cell bodies and dendrites. Light, heat,15mechanical pressure, and chemicals, such as neurotransmitters, are examples of stimuli that may generate a graded potential (depending upon the neuron). The following four steps describe the initiation of an impulse to the resetting of a neuron to prepare for a second stimulation: 1. Action potential. Unlike a graded potential, an action potential is capable of traveling long distances. If a depolarizing graded potential is sufficiently large, Na+ channels in the trigger zone open. In response, Na+ on the outside of the membrane becomes depolarized (as in a graded potential). If the stimulus is strong enough—that is, if it is above a certain threshold level—additional Na+ gates open, increasing the flow of Na+ even more, causing an action potential, or complete depolarization (from 70 to about +30 millivolts). This in turn stimulates neighboring Na+ gates, farther down the axon, to open. In this manner, the action potential travels down the length of the axon as opened Na+ gates stimulate neighboring Na+ gates to open. The action potential is an all-or-nothing event: When the stimulus fails to produce depolarization that exceeds the threshold value, no action potential results, but when threshold potential is exceeded, complete depolarization occurs. 2. Repolarization. In response to the inflow of Na+, K+ channels open, this time allowing K+ on the inside to rush out of the cell. The movement of K+ out of the cell causes repolarization by restoring the original membrane polarization. Unlike the resting potential, however, in repolarization the K+ are on the outside and the Na+ are on the inside. Soon after the K+ gates open, the Na+ gates close. Hyperpolarization. By the time the K+ channels close, more K+ have moved out of the cell than is actually necessary to establish the original polarized potential. Thus, the membrane becomes hyperpolarized (about 80 millivolts). 3. Refractory period. With the passage of the action potential, the cell membrane is in an unusual state of affairs. The membrane is polarized, but the Na+ and K+ are on the wrong sides of the membrane. During this refractory period, the axon will not respond to a new stimulus. To reestablish the original distribution of these ions, the Na+ and K+ are returned to their resting potential location by Na+/K+ pumps in the cell membrane. Once these ions are completely returned to their resting potential location, the neuron is ready for another stimulus.
Name the part of neuron:
(a) where information is acquired.
(b) through which information travels as fast as electrical impulse.
notes on control and cordination
difference between synapse and neuromuscular junction? plzzz answer it!!!!
What is the difference between reflex action and reflex arc?
differences between nervous control and chemical control
What is Reflex Arc? Draw neat diagram of the components in a reflex arc. Why do impulses flow only only in one direction in a reflex arc?
What is structural and functional unit of nervous system? Name its any two components?
what is difference b/w tropic and nastic movements in plants ? plzzz ans it fast.
Is sleeping a voluntary or involuntary action? Explain
name two hormones secreted by pancreas. write ther functions
explain why brain and spinal cord are considered as central nervous system.
answrr fastt plzz..:/
is there any difference in how sugar and food taste if your nose is blocked? if so, why might this be happening?
if we cut our vein or nerve we will die after 5 to 10 mins but if we cut our hand from the elbow or shoulder we don't die. why?
design an experiment to demonstrate hydrotropism
Write differences between exocrine glands and endocrine glands
define control and co-ordination
Name the part of brain which controls
How does our body respond when adrenaline is secreted into the
1.(a) design an experiment to demonstrate positive and negative geotropism.
(b) give reasons for the following -
(1) use of iodised salt is adviced
(2) salivation is considered an involuntary action
(3) the brain is surrounded by fluid.
phototropism occur in plants?
Name Any Two Substances Which Are Selectively Re-Absorbed As The Urine Flows Along The Tube Of Nephron.
how does the nervous tissue cause action?
Write two differences between response of plants and response of amimals to stimuli.
How do muscle cells move?
How is spinal cord and brain protected in the human body???
Where does the electrical impulse gets converted into chemical signal for onward transmission?
what is a reflex action? explain briefly its mechanism in humans. three mark question.
What is the role of the brain in reflex action?
What happens at the synapse between two neurons?
Which equipment is used to facilitate breathing during serious breathing problems?
What Is Geotropism?(in plants)
Give the Limitations of Nervous System.
How does chemical coordination take place in animals?
Aututrophs synthesise food for living world.Justify this statement in one sentence only interconnecting autotrophs and heterotrophs.
Name two tissues which provide contol and coordination in animals.
Draw the structure of a neuron and explain its function.
what happens at the synapse between two neurons
explain the structure and function of a nephron.
Salivation and vomiting are controlled by
what is the name of the tissue present in the brain
15. (a) Two conductors A and B of resistances 5 ohm and 10 ohm respectively can be arranged in parallel and later on in series. In each arrangement, the total voltage applied across it is 20 volts. In which arrangement will the voltage across A and B be the same and in which case will the current flowing through A and B be the same?
(b) Calculate the total resistance for each arrangement.
Give 5 examples of reflex actions.
a block of mass 10 kg is pulled with a constant speed on a rough horizontal plane with a force of 19.6 n. the co-officient of friction is....?
What is the difference between enzymes and hormones?
Give the differences and similarities betweem coordination in animals and coordination in plants.
1. differentiate between nastic and tropic movement.( 3 points)
2. differentiate between receptors and effectors.(3 points)
Why do the Mimosa pudica plant leaves droop when touched? exlpian
Define nerve impulse. Which structure in a neuron helps to conduct a nerveimpulse:a. Towards the cell body.b. Away from the cell body.
define hormone. write four characteristic of hormones in humans.
what is reflex arc?how does it works?explain with a diagram.
Q3. A Leaf shaped gland is present above the intestine. The sceretion of this gland regulates the metabolism of sugar in blood.
(a) Name this gland and its secretions.
(b) Is a mixed gland? Give reason for your answer.
what is reflex action?explain the mechanism of reflex action with a suitable example.
What are phytohormones ? Name any two phytohormones along with one fucntion of
what does electrical impluses mean....plzzz explain!!!
What is the difference between Cerebrum and Cerebellum...??? (in points plz)
justify that pancreas and gonads perform dual function .
Which signals will get disrupted in case of spinal cord injury ?
List the three kinds of blood vessels of human circulatory system and write their
Why doesn't the lung collapse even after forceful expiration?
Why do impulses flow only in one direction in a reflex arc?
Why do blood vessels look blue under the skin?
Nervous and hormonal system together performs the function of control and coordination in human beings. Justify the statement.
Explain different types of tactic movement.
what is the significance of reflex action?
plzz answrr fastt...:/
what are hydrocarbon?write the name and the general formula of (i) saturated hydrocarbons, (ii) unsaturated hydrocarbons, and draw the structure of one hydrocarbons of each type.how can an unsaturateds hydrocarbon be made saturated?
Explain with the help of diagram how reflex action take place?
name the hormone secreted by thyroid gland and state its functions. why is it improtant for us to iodised salt in ourdeit name the disease caused due to deficiency of iodine and mention its symptoms
Give reason why endocrine glands release their secretions into blood?
expand 3F, 4S- gland
examples of voluntary and involuntary actions
what is reflex action?explain with examples.
Why do multicellular organisms need another means of communication between cells beside nervous co-ordination?
Copyright © 2021 Aakash EduTech Pvt. Ltd. All rights reserved.
E.g: 9876543210, 01112345678
We will give you a call shortly, Thank You
Office hours: 9:00 am to 9:00 pm IST (7 days a week)